Device for actuating the brakes of motor vehicles



Jn. 14, 1930. K. MAYBAcl-l DEVICE FOR ACTUATING THE BRAKES OF MOTORVEHICLES Filed NOV. 417, 1924 F 'z I rIlII/IIIIII E'IIIII1WIIIIILWIIIIIAVIIIII 1117912 for Patented Jan. 14,

l `uNrLeD STATES PATE-NT oFfFl'ca mm. mannen, oF FRIEDRIGHSHAFEN,GERMANY, Assioma To THE man MAY- BACH AM'ILORIENBAU' GESELLSCHAFT MITRICHSHAFEN, GERMANY i BESCHRNKTER HAFTUNG, OF FRIED- 'DEVICE FORACTUATING THE BRAKS 0F MOTOR YEHIGLII'S Application filed November 17,1924, Serial No. 750,504, and in Germany December 22, 1923.

My -invention relates to brakes of motor vehicles and more especially tobrakes of this kindl in which a' hydraulic servo-motor is made use of.

Object of my 'invention is to provide for perfect sensitiveness of theoperating means of combined brakes where direct pressure as well aspressure resulting from a servo-motor actuate the brakes. cording to myinvention, for a certain predetermined angle of the brake lever thebrak-I ing stress is derived only from the lever, whereas on furtherinclination of the brake lever the'serVo-motor is put into operationthereby causing its auxiliary pressure also r to act on the brakes. Iprefer to have the direct applicationof the braking stress alone workingup to approximately half the normal braking effect and the servo-motorto set in from this limit upward..

It will be of great advantage to the driver whileapplying the brakesgradually Aif the resistance he has to overcome also increasesgradually. That is why I provide a spring with increasing resistancebetween the brake lever and the brake block in the controlling apparatusfor direct operation. Furthermore the arrangement in combination withthe servomotor may be so that while direct application of the brakingstress takesplace the controlling device of the servo-motor allows for agradual starting of this motor but this being only sufiicient toovercome the normal resistances in the lever system and that of thenecessary adjusting spring. In such cases where a pressure valvecontrols the servo-motor and where a spring is interposed between thebrake lever 'and said valve the above mentioned end may be attainedsimply by interposing a second spring between lever and valve adapted toeXert only low pressure on the valve sufficient to ascertain the aboveaction whereas the other spring is stronger and For this purpose, ac'-`of the servo-motor by means of the main engine of the vehicle, as thereare brakes provided which can be operated independently fromthe'servo-motor. Furthermorethe liquid used in the servo-motor may belubricating oil. This rsimplifies the whole arrangement.

Having given a general description of my invention I now want to pointit out more in detail referring to the drawings which repres'ent anexample embodying my invention.

Fig. 1 is a diagrammatic longitudinal section through a device of thetype described.

Fig. 2 is a portion of Fig. 1 on a larger scale showing a variation inthe spring arrangement between the brake lever and the valve'of theservo-motor.

In Fig. l brake lever z' has an arm 1' adapted to press on spring s andan arm lc adapted to press on spring m. Spring m is situated on a rodforming continuation of piston rod o,

.to be mentioned later, and bears at one end against collar Z slidablymounted onl said rod, at the other end it bears against collar fn,rigidly connected to said rod. By means of lever o the foot pressureexerted on lever z' in the direction of arrow A is transmitted toVconstant pressure and is fed to'cylinder e from a revolving pump a bymeans of wheel a in the direction of arrow c. This liquid in cylinder epresses on piston u after valve t has been partially or totally closedthereby partially or totally 'preventing the liquid from escapingthrough outlet f and returning through pipe gto oil well h. Oil pressureon piston u by means of rod u and its e continuation is transmitted tocollar 'n and therefrom to brake block g, thus causing a desired brakingeffect. Oil pump a which is driven from the engine (not shown)inconnection with a second wheel a `feeds the lubricating oil to the enine. Furthermore in the piping d arrange between oi'l puni a andcylinder e a suction valve 'w is provide adapted to allow for a owing inof oil from Well la, in case of the engine being at rest and piston ubeing moved to the right vby foot pressure passing over arm c and collar'n to piston rod la. f f The operation of the mechanism is as follows: 1

Lever i is pressed down by foot so that l ausser said mechanical system;said brake lever opf erating said valve only after said mechanical ystemhas been working thelbrake to a prearm lc presses on collar l, andthereby under compression of spring m acts on .collar n which by meansof lever o brin brake block g to act. So long as arm r oesl not touchspring s the braking effect is exerted only/ by foot pressure. Whenlever is pressed down further so that arm r presses on spring s thiscauses Valve t which is held open by the pressure of the liquid fromcylinder e gradually to close. Thereby the increase of oil pressure inthe cylinderl e causes piston u to move to the' right and over collar nand lever o also to act on the braking block q.

In Fig. 2 an additional weaker spring a: v Vis providedrbetweena'rmfrand valve t for the purpose of 'ascertaining a gradual startnof/ theservo-motor.

I do not want to limit myself to the details described or shown in thedrawings as many variations will occur to those skilled in the art. Y

What I claim is: c

1. A brake control system comprising va mechanical system for directappllcation 'of the braking stress to a brake; a brake lever forcontrolling said system; and a hydraulic servo-motor controlled b thesame brake lever; comprising a c lin er, a piston in said cylinder, apiston r projecting out of said' cylinder, said cylinder having anopening adapted for letting in liquid under pressure, and havingan-outlet controlled by a valve; said valve being controlled by saidbrake lever; and said piston rod being connected to said mechanicalbrake system; said brake etermined degree of braking effect."

In testimony whereof I aliix my si ature. KARL MAYB CH.

the braking stress to abrake; a brake lever' for controlling said systemand a hydraulic servo-motor controlled by' the same, brake lever;comprising a c linder, a piston in said cylinder, a piston ro projectingout of said cylinder, said cylinder having anvopening adapted forletting in liquid under pressure, and having an outlet controlledby avalve; said valve being controlled by said brake lever; and said pistonrod being connected to said mechanical brake system, said connectionallowing for operation of the brake

